US4992340A - Intrinsic safe battery having self test capability - Google Patents

Intrinsic safe battery having self test capability Download PDF

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Publication number
US4992340A
US4992340A US07/340,828 US34082889A US4992340A US 4992340 A US4992340 A US 4992340A US 34082889 A US34082889 A US 34082889A US 4992340 A US4992340 A US 4992340A
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Prior art keywords
battery
means
coupled
scr
contacts
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US07/340,828
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James L. Tidwell
Henry A. Bogut
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Motorola Solutions Inc
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Motorola Solutions Inc
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Priority to US07/340,828 priority Critical patent/US4992340A/en
Assigned to MOTOROLA, INC., A CORP. OF DE reassignment MOTOROLA, INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BOGUT, HENRY A., TIDWELL, JAMES L.
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits

Abstract

A battery having a self testing feature for its intrinsic safety circuitry is provided. The battery uses light emitting diodes to indicate the operation of safety circuit in the battery. The safety circuitry of the battery may be tested by providing a short across the battery terminals, if the associated circuitry is operational the light emitting diode will light. This feature will also indicate, when the load across the battery is shorted.

Description

TECHNICAL FIELD

This invention relates generally to batteries, and more particularly to intrinsically safe batteries.

BACKGROUND ART

In order to safely use a battery in a hazardous environment, such as coal mines where the possibility of explosions exits, a safety feature is needed to prevent spark generation when the battery contacts are inadvertently shorted. Conventional batteries for portable two-way radios used in such environments, incorporates protective circuitry to achieve this safety feature. The protective circuitry, upon detection of a short on the battery positive and negative contacts, provides for an open circuit between one of the cells terminal and the corresponding battery contact, thereby preventing spark generation. Although the current protective circuitry insures protection when the battery contacts are shorted, no provision exists to test the functionality of the protective circuitry prior to use in the hazardous environment. Thus, a portable radio user may not know that the protective circuitry has failed and mistakenly believe that that the radio and battery are safe.

Additionally, intrinsically safe batteries and non-intrinsically safe batteries have the same general appearance. Therefore, these batteries are usually distinguished from one another by a label placed on the battery housing. This distinguishing method may cause confusion during manufacturing or during use of the battery, causing a factory operator (or a user) to inadvertently place a non-intrinsically safe battery on a radio designated for use in hazardous environments. Therefore, a more reliable distinguishing method is desirable.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an intrinsically safe battery having self test capability.

Briefly, according to the invention, a battery having an indicator for self testing is provided. The battery comprises energy storage means coupled to a mean for controlling supply of energy to a device. The supply of energy will be permitted during normal operation, and prohibited in response to a short across the battery contacts. The indicator mean is automatically activated when the battery terminals are shorted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, is an schematic circuit diagram of one embodiment of a preferred intrinsically safe battery according to the invention.

FIG. 2, is an schematic circuit diagram of another embodiment of a preferred intrinsically safe battery according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a battery 100 is coupled to a radio 200 via a positive contact 140 and a negative contact 150. The battery 100 comprises a plurality of battery cells 110 having a positive terminal coupled to the collector of a Darlington (pair) transistor 121. A resistor 122 is coupled between the collector and the base of the transistor 121 to provides a base bias current. The emitter of transisitor 121 is coupled to the positive contact 140. The base of the transistor 121 is coupled to the anode of a silicon controlled rectifier (SCR) 123. The cathode of the SCR 123 is coupled to negative terminal of the plurality of cells 110. The negative terminal of the cells 110 is coupled to the negative contact 150 through a sensing resistor 127. A resistor 125 is coupled between the gate of SCR 123 and the battery contact 150. A capacitor 124 is coupled between the gate of SCR 123 and negative terminal of cells 110. A light emitting diode (LED) 130 is coupled across the collector and emitter of transistor 121 through a resistor 131.

In describing the operation of battery 100 two mode will be considered: First the normal operation, second when the battery contacts 140 and 150 are shorted.

During normal use of the battery 100 and radio 200, the base current provided by resistor 122 turns on transistor 121. Thus the energy stored in cells 110 is supplied to the radio 200. A voltage drop across sensing resistor 127, corresponding to current supplied by the battery 100, charges the capacitor 124 through the resistor 125. The capacitor 124 maintains the gate voltage for SCR 123. The sensing resistor 127 and the resistor 125 have been selected such that the gate voltage of SCR 123 will be below the firing threshold during peak current operation (i.e., when radio is in transmit mode). The LED 130 remains off during the normal operation, due to the short circuit provided by conducting transistor 121.

When the battery contacts 140, and 150 are shorted, the voltage drop across sensing resistor 127 charges capacitor 124 to a voltage higher than firing threshold of SCR 123 causing the SCR 123 to turn on. When the SCR 123 is turned on the current flows through resistor 122 and SCR 123, and base bias current of transistor 121 is removed. The removal of base bias current turns off the transistor 121, thereby causing an open circuit between positive terminal of battery 110 and battery contact 140. The open circuit across transistor 121 turns on the LED 130, to indicates that a short is across the contacts 140 and 150. Accordingly, the LED 130 is an indicating mean for proper operation of the transistor 121.

Due to latching characteristic of SCR, the SCR 123 will remain on even after the short across contacts 140 and 150 is removed. A test or reset pad 128 is provided on the anode of SCR 123 in order to return (reset) the battery to its normal operating mode, by presenting a momentary short across negative terminal 150 and pad 128. A person of ordinary skill in the art may appreciate that, the SCR 123 could be replaced by a transistor (not shown) for detection of a short across the contacts 140 and 150. By using a transistor, the battery will return to its normal operating mode automatically, when the short across the battery contacts is removed.

Accordingly, The transistor 121 and associated circuitry constitute a means for switching, the SCR 123 and associated circuitry constitute means for controlling the switching means, and the LED 130 and associated circuitry constitute means for indicating. The above circuitry are contained in a block 120 which comprise the intrinsic safety feature of the invention. In order to insure optimum reliability in design of intrinsically safe batteries, it is customary to provide redundancy for protective circuitry. Therefore it may be desirable to cascade duplicates of circuitry described in block 120 in subsequent blocks 120'. When a short is caused across the battery contacts, the block circuitry being most sensitive to proper gate voltage will be activated.

Referring to FIG. 2 another embodiment of the invention is shown. The battery 100' is similar in operation to battery 100 described in FIG. 1. The LED 130' is coupled between base of transistor 121' and anode of SCR 123'. During normal operation the LED 130' will remain off, since SCR 123' is not conducting. When terminals 140' and 150' are shorted the SCR 130' will be conducting, thereby LED 130' will be turned on. In this embodiment of the invention the LED 130' will indicate whether the SCR 123' is conducting or not.

The preferred embodiments described in FIG. 1 and FIG. 2 may be used to test a intrinsically safe battery in a hazardous environment, by shorting the battery contacts and verifying lighting of LED, prior to utilization. The presence of LED on the battery housing may also be used to distinguish intrinsically safe batteries from non-intrinsically safe batteries.

Claims (7)

What is claimed is:
1. A battery having a first and second contact, comprising:
at least one battery cell having first and second terminals,
means for switching coupled between said first terminal and said first contact,
means for controlling said switch coupled to said battery cell and switching means, responsive to detection of a momentary short between first and second contacts, to open said switching means, and provide a constant current through said battery cell;
means for indicating when a short is present between said first and second contacts.
2. The battery of claim 1, wherein said indicating means is coupled across said switching means.
3. The battery of claim 1, wherein said indicating means is coupled to said controlling means.
4. The battery of claim 1, wherein said switching means comprise transistors.
5. The battery of claim 1, wherein said controlling means comprise silicon controlled rectifiers.
6. The battery of claim 1, wherein said indicating means comprise light emitting diodes.
7. The battery of claim 1, wherein said battery is used on a two-way portable radio.
US07/340,828 1989-04-20 1989-04-20 Intrinsic safe battery having self test capability Expired - Lifetime US4992340A (en)

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US07/340,828 US4992340A (en) 1989-04-20 1989-04-20 Intrinsic safe battery having self test capability

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US07/340,828 US4992340A (en) 1989-04-20 1989-04-20 Intrinsic safe battery having self test capability

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US4992340A true US4992340A (en) 1991-02-12

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Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5258244A (en) * 1991-12-09 1993-11-02 Hughes Aircraft Company Reversible automatic cell bypass circuit
US5298346A (en) * 1992-07-27 1994-03-29 Motorola, Inc. Battery identification system
US5363030A (en) * 1991-09-16 1994-11-08 Motorola, Inc. Battery having a transistor switch for supplying energy
US5412138A (en) * 1990-06-14 1995-05-02 Elf Atochem S.A. Phosphorus-containing acrylic compounds and polymers thereof
EP0666630A1 (en) * 1994-02-02 1995-08-09 Nec Corporation Overcurrent preventing circuit
US5460901A (en) * 1992-09-29 1995-10-24 Nokia Mobile Phones Limited Battery identification
US5587250A (en) * 1995-09-27 1996-12-24 Motorola, Inc. Hybrid energy storage system
US5622789A (en) * 1994-09-12 1997-04-22 Apple Computer, Inc. Battery cell having an internal circuit for controlling its operation
US5670266A (en) * 1996-10-28 1997-09-23 Motorola, Inc. Hybrid energy storage system
US5716725A (en) * 1996-06-06 1998-02-10 Motorola, Inc. Method apparatus for indicating improper coupling of a power source to an electronic device
US5738919A (en) * 1996-11-25 1998-04-14 Motorola, Inc. Energy storage system
US5750285A (en) * 1994-08-25 1998-05-12 Yuasa Corporation Life indicator and lead-acid storage battery with life indicator
US5783322A (en) * 1995-11-09 1998-07-21 Sony Corporation Secondary battery pack
US6087812A (en) * 1997-06-13 2000-07-11 Motorola, Inc. Independent dual-switch system for extending battery life under transient loads
US6117585A (en) * 1997-07-25 2000-09-12 Motorola, Inc. Hybrid energy storage device
US6295193B1 (en) 1999-01-22 2001-09-25 Telefonaktiebologate Lm Ericsson (Publ) Electronic circuit board, an arrangement comprising an insulating material and an electronic circuit board
US6469619B1 (en) 1999-04-20 2002-10-22 The United States Of America As Represented By The Department Of Health And Human Services Intrinsically-safe roof hazard alert module
US20050151657A1 (en) * 2002-06-19 2005-07-14 Lockhart Bradley W. Battery monitor with wireless remote communication
WO2006098157A3 (en) * 2005-03-17 2007-11-01 Toyota Motor Co Ltd Monitoring device for power supply system
US20100323766A1 (en) * 2009-06-22 2010-12-23 Motorola, Inc. Method and apparatus for intrinsically safe operation of a communication device
US20110045323A1 (en) * 2009-08-21 2011-02-24 Motorola, Inc. Current limiting apparatus and method
US20110086256A1 (en) * 2009-10-08 2011-04-14 Etymotic Research Inc. Rechargeable Battery Assemblies and Methods of Constructing Rechargeable Battery Assemblies

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5618375A (en) * 1979-07-23 1981-02-21 Nissan Motor Co Ltd Battery liquid level alarm
JPS57196481A (en) * 1981-05-27 1982-12-02 Yuasa Battery Co Ltd Inspection of storage battery
JPS5859568A (en) * 1981-10-05 1983-04-08 Nissan Shatai Co Ltd Alarm apparatus for battery
US4727006A (en) * 1986-02-12 1988-02-23 The United States Of America As Represented By The Secretary Of The Army Method of monitoring electrochemical cells

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5618375A (en) * 1979-07-23 1981-02-21 Nissan Motor Co Ltd Battery liquid level alarm
JPS57196481A (en) * 1981-05-27 1982-12-02 Yuasa Battery Co Ltd Inspection of storage battery
JPS5859568A (en) * 1981-10-05 1983-04-08 Nissan Shatai Co Ltd Alarm apparatus for battery
US4727006A (en) * 1986-02-12 1988-02-23 The United States Of America As Represented By The Secretary Of The Army Method of monitoring electrochemical cells

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5412138A (en) * 1990-06-14 1995-05-02 Elf Atochem S.A. Phosphorus-containing acrylic compounds and polymers thereof
US5363030A (en) * 1991-09-16 1994-11-08 Motorola, Inc. Battery having a transistor switch for supplying energy
US5258244A (en) * 1991-12-09 1993-11-02 Hughes Aircraft Company Reversible automatic cell bypass circuit
US5298346A (en) * 1992-07-27 1994-03-29 Motorola, Inc. Battery identification system
US5460901A (en) * 1992-09-29 1995-10-24 Nokia Mobile Phones Limited Battery identification
US5570255A (en) * 1994-02-02 1996-10-29 Nec Corporation Overcurrent preventing circuit
EP0666630A1 (en) * 1994-02-02 1995-08-09 Nec Corporation Overcurrent preventing circuit
US5750285A (en) * 1994-08-25 1998-05-12 Yuasa Corporation Life indicator and lead-acid storage battery with life indicator
US5622789A (en) * 1994-09-12 1997-04-22 Apple Computer, Inc. Battery cell having an internal circuit for controlling its operation
US5645949A (en) * 1994-09-12 1997-07-08 Apple Computer, Inc. Battery cell having an internal circuit for controlling its operation
US5587250A (en) * 1995-09-27 1996-12-24 Motorola, Inc. Hybrid energy storage system
WO1997012415A1 (en) * 1995-09-27 1997-04-03 Motorola Inc. Hybrid energy storage system
US5783322A (en) * 1995-11-09 1998-07-21 Sony Corporation Secondary battery pack
US5716725A (en) * 1996-06-06 1998-02-10 Motorola, Inc. Method apparatus for indicating improper coupling of a power source to an electronic device
WO1998019357A1 (en) * 1996-10-28 1998-05-07 Motorola Inc. Hybrid energy storage system
US5670266A (en) * 1996-10-28 1997-09-23 Motorola, Inc. Hybrid energy storage system
US5738919A (en) * 1996-11-25 1998-04-14 Motorola, Inc. Energy storage system
WO1998024140A1 (en) * 1996-11-25 1998-06-04 Motorola Inc. Energy storage system
US6087812A (en) * 1997-06-13 2000-07-11 Motorola, Inc. Independent dual-switch system for extending battery life under transient loads
US6117585A (en) * 1997-07-25 2000-09-12 Motorola, Inc. Hybrid energy storage device
US6295193B1 (en) 1999-01-22 2001-09-25 Telefonaktiebologate Lm Ericsson (Publ) Electronic circuit board, an arrangement comprising an insulating material and an electronic circuit board
US6469619B1 (en) 1999-04-20 2002-10-22 The United States Of America As Represented By The Department Of Health And Human Services Intrinsically-safe roof hazard alert module
US20050151657A1 (en) * 2002-06-19 2005-07-14 Lockhart Bradley W. Battery monitor with wireless remote communication
US7394394B2 (en) * 2002-06-19 2008-07-01 Tarma, L.L.C. Battery monitor with wireless remote communication
US20080129249A1 (en) * 2005-03-17 2008-06-05 Toyota Jidosha Kabushiki Kaisha Monitoring Device for Power Supply System
WO2006098157A3 (en) * 2005-03-17 2007-11-01 Toyota Motor Co Ltd Monitoring device for power supply system
US7746031B2 (en) 2005-03-17 2010-06-29 Toyota Jidosha Kabushiki Kaisha Monitoring device for power supply system
US20100323766A1 (en) * 2009-06-22 2010-12-23 Motorola, Inc. Method and apparatus for intrinsically safe operation of a communication device
US8805455B2 (en) 2009-06-22 2014-08-12 Motorola Solutions, Inc. Method and apparatus for intrinsically safe operation of a communication device
US20110045323A1 (en) * 2009-08-21 2011-02-24 Motorola, Inc. Current limiting apparatus and method
US8305725B2 (en) 2009-08-21 2012-11-06 Motorola Solutions, Inc. Current limiting apparatus and method
US20110086256A1 (en) * 2009-10-08 2011-04-14 Etymotic Research Inc. Rechargeable Battery Assemblies and Methods of Constructing Rechargeable Battery Assemblies
US8460816B2 (en) * 2009-10-08 2013-06-11 Etymotic Research, Inc. Rechargeable battery assemblies and methods of constructing rechargeable battery assemblies

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